What's the gain of having a single checksum for two areas compared to 2 checksums for two separate areas?In the end the code computing the checksum at runtime has to know the boundaries of the two areas explicitely anyway. I doubt that the single checksum area uses less flash as it explicitely has to combine the two checksum while the 2 checksum version can just reuse the same code twice.

It's a different story when we have 10 pages with the same range in each page, then a combined checksum would help a bit, but I doubt much.Daniel